Small augerhead type hydraulic dredge systems operating in areas containing debris often malfunction due to clogging of the system's pump impeller intake eye. Present dredging systems use screens that are readily clogged; for example, see U.S. Pat. No. 1,705,428 entitled "Dredging Apparatus" by Twiford where a screen is used in the drag arm up-take assembly. Clean-out boxes, similar to the transition box of the instant invention, are not self-cleaning and generally do not allow clean flow of dredge spoils; for example, see York et al.'s U.S. Pat. No. 2,250,693 entitled "Trap for Dredger Suction Pipe."
Other devices used to resolve this problem include rock boxes and macerators; neither of which are appropriate for small augerhead type hydraulic dredge operations. Examples of these features are taught in U.S. Pat. No. 3,738,029 entitled "Dredging Head with Pivotally mounted Mud Shield" by Harmon which shows an augerhead type dredge assembly with dual auger flites as in the instant invention. This teaching is incorporated by reference to show design requirements for a horizontal pair of spiral augers that rotate for digging and moving dredge materials towards a spoils inlet for transfer to the system's slurry or dredge pump.
The instant invention's grate/cutter device and transition box resolve the above mentioned problems. Accordingly, several objects and advantages of the invention herein include providing: i) a cutter/grate device for a small augerhead type hydraulic dredge system with grates that conform with a center arcuate member of augerhead's cutter to prevent ingestion of debris into the system's pump by cutting up vegetation and excluding debris prior to entry into the pump's impeller eye; and ii) a transition box structure behind the augerhead's shroud that has a back-flush and a manual cleanout door. These features as well as others allow efficient dredging operations that are readily apparent to those skilled in the art.